Ilulissat

The Arctic

Seqinersuup alakkaqqilerpaiqaqqavut kusanartorsuitqamani neriuutit ikippaimaqaasiuartakkavut*

(The sun has begun to appear againOur beautiful mountainshave ignited hopes within usthat we have missed all this time)

In mid-January every year, people in Greenlandgather to greet the returning light. In Ilulissat,they sing this greeting, waiting for the sun topeek above the horizon. Its first rays manageonly a brief glimmer, but the promise theybring is strong, the hope of summer:

Seqinersuup qimaatilereerpaaukiorsuup kaperlassua

(The sun has put to flight winter’s long gloom)

Dark winters followed by long summer daysare one of the most profound features of theArctic, and are responsible for the ubiquitoussnow and ice. The spring and summer sunbrings enough energy to sustain life, but notenough to melt all the frozen water or thefrozen ground. Ice and snow have thereforeshaped and are still shaping the northernlandscape.

The Arctic is not a uniform environment.Different geological histories, warm and coldocean currents, and varying weather patternsbring diversity to the scene. A circumpolarvoyager will meet everything from the perma-nent ice cover of the High Arctic to the borealforest of the subarctic, with the wide expanseof tundra in between.

This chapter describes the land, the seas, andthe climate of the AMAP region, setting thestage for the rest of the report.

*Greenlandic text: Samuel Knudsen, Kangersuatssaat

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What is the Arctic?Arctos is Greek for bear, and the Arctic regionderives its name from the stellar constellationof Ursa major, the Great Bear. A common geo-graphical definition of the Arctic is the areanorth of the Arctic Circle (66°32'N), whichencircles the area of the midnight sun.

July temperatures create a climatic definition

From an environmental point of view, definingthe Arctic solely on the basis of the ArcticCircle makes little sense. Vegetation types fol-

low climate more than solar radiation. Clima-tically, the Arctic is often defined as the areanorth of the 10°C July isotherm, i.e. north ofthe line or region which has a mean July tem-perature of 10°C.

The climate is highly influenced by regionalweather patterns and ocean currents. In theAtlantic Ocean west of Norway, the warmingeffect of the North Atlantic Current (an exten-sion of the Gulf Stream) pushes this 10°C iso-therm north of the Arctic Circle, so that onlythe northernmost parts of Scandinavia areincluded in this definition. In North Americaand northeast Asia, the isotherm is pushedsouth by cold water and cold air moving downfrom the Arctic Basin. Here the Arctic wouldinclude northeastern Labrador, northern Que-bec, Hudson Bay, central Kamchatka, and theBering Sea. Greenland and most of Icelandalso fall north of this isotherm.

A treeline boundary would move Arctic limits further south

A third definition of the Arctic region uses thetreeline as the boundary. Simply put, the tree-line is the border between southern forests andnorthern tundra. It is a transition zone wherecontinuous forest gives way to tundra with

60°N

70°N

80°N

Arctic Circle

10°C July isotherm

Treeline

Marine

AMAP

Boundaries of the Arctic

Southern boundaries of the High Arctic and the subarctic delineated on a basis of vegetation

High Arctic

subarctic

The Arctic Circlemarked in the terrainnext to the railroad inSweden.

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sporadic stands of trees and finally to treelesstundra. In North America, the tundra-forestboundary is a narrow band, but in Eurasia it isup to 300 kilometers wide. The treeline corre-sponds with a climate zone where the coldArctic air meets warmer airmasses from far-ther south.

In some places, the treeline roughly coin-cides with the 10°C July isotherm, but acrossmuch of mainland Eurasia and North Americathe treeline is 100 to 200 kilometers south ofthe isotherm. By the treeline definition, theArctic also includes western Alaska and thewestern Aleutians.

The subarctic lies between the treeline to thenorth and the region to the south where theforest becomes dense enough to have a closedcanopy. The subarctic is also called the taiga orforest tundra. Permafrost (permanently frozenground) is only present in patches, and in sum-mer the unfrozen layer is generally thick. Thepresence of discontinuous permafrost is some-times used to define the subarctic, in contrastto the Arctic where permafrost is continuous.

Meeting of cold and warm water formsthe marine boundary

The marine boundary of the Arctic is formedwhen the water of the Arctic Ocean, cool anddilute from melting ice, meets warmer, saltierwater from the southern oceans. In the Cana-dian Arctic Archipelago, this belt is at approxi-mately 63°N and swings north between BaffinIsland and the coast of west Greenland. Offthe east coast of Greenland, the marine bound-ary lies at approximately 65°N. In the Euro-pean Arctic, the marine boundary is much far-ther north, pushed to about 80°N to the westof Svalbard by the warming effect of the NorthAtlantic Current. At the other entrance intothe Arctic, warm Pacific water flows throughthe Bering Strait to meet Arctic Ocean water atabout 72°N, forming a boundary that stretchesfrom Wrangel Island in the west to AmundsenGulf in the east.

AMAP’s boundaries

Because of the difficulty of defining the Arcticin a way that is relevant for all areas of sci-ence, AMAP does not define the Arctic butgives a guideline about the core area to be cov-ered by the AMAP assessment. The boundaryshould lie between 60°N and the Arctic Circle,with the following modifications:

• In the North Atlantic, the southern bound-ary follows 62°N, and includes the FaroeIslands, as described in ‘The Joint Assess-ment and Monitoring Programme’ of theConvention for the Protection of the MarineEnvironment of the North-East Atlantic (theOSPAR Convention). To the west, the La-brador and Greenland Seas are included inthe AMAP area.

• In the Bering Sea area, the southern bound-ary is the Aleutian chain.

• Hudson Bay and the White Sea are consid-ered part of the Arctic for the purposes ofthe assessment.

• In the terrestrial environment, the southernboundary in each country is determined bythat country, but lies between the ArcticCircle and 60°N.

The map on the opposite page shows thearea covered in this report.

Eight countries have land within the areaof AMAP’s responsibility: Canada, Denmark(Greenland and the Faroe Islands), Finland,Iceland, Norway, Russia, Sweden, and theUnited States (Alaska).

The landAbout 13.4 million square kilometers, 40 per-cent, of the AMAP area is covered by land.The map below shows the major physical-geo-graphical regions. Old crystalline shields under-lie most of eastern Canada, Greenland, andFennoscandia. Younger sedimentary rock,eroded into plains, covers large parts of Russiaand the Mackenzie River valley in Canada. Inthe Ural Mountains, in the northeastern cornerof Russia, in Alaska, and in the Yukon Territo-ries of Canada the sedimentary rock has foldedinto mountain ranges. Similar folded sedimen-tary rock forms the mountain ranges of thenorthern Canadian Arctic islands. Iceland andthe Aleutian islands are of volcanic origin.

7The Arctic

Major physical-geo-graphical regions of theArctic. Colors indicatesimilar landscape fea-tures.

East Siberian Highlands

CentralSiberianPlateau

WestSiberianLowlandUral

Mountains

East EuropeanPlain

BalticShield

NorthAtlanticIslands

Canadian Shield

ArcticIslands

InteriorPlain

North AmericanCordillera

HudsonLowlands

Ice has shaped the landscape

On a shorter time scale, ice has put its signa-ture on most of the terrestrial landscape. Someof the land is covered by glaciers, which arelarge masses of snow and ice that flow undertheir own weight. Glaciers form where themean winter snowfall exceeds mean summermelting. Melting, refreezing, and pressuregradually transform the snow to ice.

Many areas have been shaped by repeatedglaciations. In the North American and west-ern Eurasian Arctic, ice sheets have scouredthe landscape like giant bulldozers, tearingaway topsoil and broken rock. In areas with

hard crystalline granite bedrock, the glaciersleft the land dotted with depressions that filledwith water and became lakes. Glaciers thateroded the bedrock below sea level at the coastcreated deep, winding fjords. In other areas,the glaciers piled extensive moraines and sedi-mentary deposits on top of the bedrock.

Some of the land is still rebounding afterbeing pressed down by the weight of the icesheets during the latest glaciation. Along thecoasts, the land is still emerging from the sea.Around Hudson Bay, for example, the landrises at a rate of one meter per century.

Permafrost creates patterned ground andgoverns water movement

Much of the ground is frozen by permafrost,and only a thin top layer, called the active layer,thaws each summer. Permafrost is defined asground that remains frozen for at least twosummers in a row. The frozen layer can reachdepths of 1500 meters in the coldest areas ofthe Arctic. The active layer ranges between afew centimeters in the northernmost wet mead-ows to a few meters in warmer, drier areaswith coarse-grained soils. Perennially frozenground occurs throughout the Arctic and ex-tends into the forested regions to the south.Along the northern coasts, frozen groundsmeet the sea, and the permafrost extendsunder some shelf seas.

The constant freezing and thawing in per-mafrost areas makes the ground move. In theprocess, debris is sorted and rocks are forcedto the surface. In some areas this sorting hascreated extensive polygonal patterns; see fig-ures on the opposite page. Another physicalfeature is the pingo, a mound of earth thrustup by a core of ice. Pingos can be as high as 40meters. Occasionally, changes in local climateor physical disturbance of the ground can

Glacier Bay, Alaska.

Discontinuous permafrostContinuous permafrostIce cap /glacier

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Cross-sections of low-and high-centered poly-gons found in Arcticwetlands. The low-cen-tered polygons gradu-ally evolve into high-centered polygons withthe accumulation of biomass.

5 m

High-center polygons

Low-center polygons

Mineral soilSedge-moss peatSphagnum peat

Amorphous peat

IcePermafrost table

Organic-mineral mixture

Mineral soilSedge-moss peatSphagnum peat IcePermafrost table

cause the permafrost to melt. In some cases,this causes the ground to sink, and the depres-sion fills up with water, creating so-called ther-mokarst lakes, which are unique to the Arctic.

Permafrost governs the fate of water in theArctic landscape. For example, groundwaterformation is much slower in frozen groundthan in unfrozen ground. The groundwatercan be on top of, in cracks within, or under-neath the permafrost layer.

In spring, permafrost contributes to flood-ing. Eighty to ninety percent of the freshwaterinput to the land occurs during the two to threeweeks of snowmelt in spring. Instead of seepinginto the ground, the meltwater flows over thefrozen surface and into streams, rivers, lakes,and various wetlands, which cover vast areason the flat plains.

The lack of oxygen in the waterlogged soilof wetlands delays the decomposition of plantmatter and results in a build-up of organic ma-terials, such as peat and humic substances. Indrier areas where the water can escape, such assteep slopes and high narrow ridges, increasedbacterial activity in the soil leads to a lowercontent of organic matter. These areas often

Groundwater percolating throughout the year percolating only during the warm season

Substrate

Clay and silt

Gravel

Permafrost

Active layer

Depth ofsummer thawing(bottom of active layer)

Impervious ground at surfaceforces water to percolate throughthe unfrozen part (talik) in permafrost

Small lake

Well drained site

Poorly drained site

River

Groundwater in perma-frost.

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Tundra, Kolyma,Russia.

Driftwood and pingo,Tuktuyaktuk, Yukon,Alaska

have a characteristic soil profile caused by theredistribution of soil particles and chemicals.

Arctic rivers also owe much of their charac-ter to the permafrost. Because the ground hassuch a limited ability to store water, the springflood can be violent, undercutting the riverbank and causing extensive erosion along itspath. Ice jams add to the uneven flow and ero-sion. The rivers thus carry huge amounts ofsediments that are deposited along their courseand in wide deltas.

Natural resources are abundant

The circumpolar region has numerous largedeposits of fossil fuels and minerals. Examplesinclude nickel in the vicinity of Norilsk in Rus-sia, the recently discovered diamond depositsin the Northwest Territories in Canada, coal inSvalbard, and oil and gas fields at Prudhoe Bayin Alaska and in many other areas that are de-scribed in the chapter Petroleum Hydrocarbons.

The AMAP region also contains many re-newable resources. Forests supply fuel forenergy and material for pulp and paper pro-duction. Both marine and freshwater ecosys-tems are important for commercial fishing.Powerful rivers provide hydroelectric power,while geothermal energy is used for heating insome areas.

The seasThe marine areas within AMAP’s boundariescover approximately 20 million square kilome-ters. These include the Arctic Ocean, the adja-cent shelf seas (Beaufort, Chukchi, East Siberi-an, Laptev, Kara, and Barents Seas), the WhiteSea, the Nordic Seas (Greenland, Norwegian,and Iceland Seas), the Labrador Sea, Baffin Bay,Hudson Bay, the Canadian Arctic Archipelago,and the Bering Sea. The narrow Bering Straitconnects the Arctic Ocean and the Bering Sea(and the Pacific Ocean), while the main con-nection between the Arctic Ocean and thenortheast Atlantic Ocean (Nordic Seas) is viathe deep Fram Strait and the Barents Sea. Thereare two major basins in the Arctic Ocean, theCanadian Basin and the Eurasian Basin, sepa-rated by the transpolar Lomonosov Ridge.

The Arctic Ocean has a vast continentalshelf, extending from northern Scandinaviaeastward to Alaska. All the Eurasian marginalseas are located over this shelf, which has awidth of up to 900 kilometers off the coast ofSiberia. Off North America, the shelf extendsonly 50 to 100 kilometers from the coast.

Most of the water in the Arctic Ocean comesfrom the Atlantic Ocean via Fram Strait andthe Barents Sea, with some additional inflowfrom the Bering Strait. Rivers account for abouttwo percent of the input, a high proportioncompared with other oceans. The main outflowfrom the Arctic Ocean is via the East Green-land Current, with a minor portion flowingout via straits in the Canadian Archipelago.The water flow is further described in the figureon page 31. A prominent feature in the surfacewater is the oceanic polar front, which sepa-rates the cold, less saline surface water of theArctic Ocean from saltier, warmer water origi-nating in the oceans farther south. The posi-tion of the front is relatively stable in mostareas, moving little from year to year.

Surface water temperatures vary both sea-sonally and geographically. In the Arctic Ocean,the surface water temperature is close to freez-ing point year-round because of the ice. In theshelf areas, the sun can warm the water fromfreezing point in winter to 4-5°C during sum-mer. In areas influenced by Atlantic and Pacificwater, there may be greater seasonal variabil-ity, and the temperature remains higher than0°C throughout the year.

Salinity varies with depth and with thewater’s source. Arctic surface water is less saltythan the deep ocean water and than the surfacewaters of other oceans because of meltwaterfrom ice as well as large inputs of freshwaterfrom north-flowing rivers. The highest salinity

Erosion, Kobuk River,Alaska.

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is in water of Atlantic or Pacific origin. Thefresher water floats on top of more saline water,and the water mass is best described as havingdistinct layers with different temperatures and

salinities. This is further discussed on page 31.The halocline that separates the fresher fromthe saltier water creates a lid that keeps deeper,warm water from reaching the surface.

11The Arctic

The central Arctic Ocean.

Yukon River210 km3 per year

Mackenzie River333 km3 per year

Nelson River75 km3 per year

Northern Dvina106 km3 per year

Pechora140 km3 per year

Ob, 404 km3 per year

Yenisey, 630 km3 per year

Lena, 525 km3 per year

Kolyma132 km3 per year

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Freshwater discharge

Catchment area

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PacificOcean

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BeringStrait

East SiberianSea

LaptevSea

KaraSea

BarentsSea

North GreenlandSea

GreenlandSea

FramStrait

IcelandSea

HudsonBay

LabradorSea

BaffinBay

CanadianArctic

Archipelago

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Canadian Basin

EurasianBasin

Bathymetry of the ArcticOcean and adjacent seasand freshwater inputfrom major rivers.

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Many coasts feature semi-enclosed bodies of water

Semi-enclosed water bodies in the ArcticBasin include fjords, bays, straits, and chan-nels between islands. Many of these estuarineenvironments are important links between theterrestrial environment and the ocean becausethey act as sediment traps.

Each of the semi-enclosed bodies of wateris unique, and its environment is governed byice cover and tides. In Frobisher Bay, BaffinIsland, for example, the tides are extreme.In Lancaster Sound, Baffin Bay, an area ofopen water within sea ice, called the NorthWater Polynya, forms every year. Fjords insome regions, such as Norway, are ice-freeyear-round, due to the warming effect of theNorth Atlantic Current.

Hudson Bay in Arctic Canada is consideredpart of the AMAP area even though it extendsas far south as 51°N. The bay is ice-covered inthe winter, and gets much of its water fromrivers draining central and northeast NorthAmerica. A similar semi-enclosed body of wa-ter in the Eurasian Arctic, also heavily influ-enced by freshwater runoff, is the White Sea.

Sea ice dominates the Arctic Ocean

Ice is the most striking feature in the ArcticOcean. The perennial pack ice covers about 8million square kilometers. The total area cov-ered by sea ice changes with season, reachingits peak in March to May, at about 15 millionsquare kilometers; see figure below left.

The ice is in constant motion, following themajor currents and growing in thickness as itmoves along. The trip from one end of theArctic Basin to the other can take up to sixyears, allowing the ice to grow as thick asthree meters or more; see the map on page 32.

Forces from winds, upwelling water, andwater currents create strains and stresses onthe moving ice, which lead to patches of openwater even in the depths of winter. In someareas, these leads and polynyas are formedevery year and serve as important gatheringgrounds for marine wildlife and as huntinggrounds for Inuit. They also represent areas ofhigh energy exchange between the ocean andthe atmosphere. During summer, about 10 per-cent of the pack ice area is actually open water.

In other areas, the ice is pushed into hugehummocks and pressure ridges. The height ofhummocks is typically 4 to 5 meters, but theysometimes reach heights of 12 to 15 meters.An underwater ice ridge can extend 30 to 40meters below the surface.

Shelf seas mainly have first-year ice, whichbuilds from the coast and the ice edge duringwinter. Offshore winds often separate the packice from the landfast ice.

March ice edge

Septemberice edge

Shallow, warm

Deep, cold

The polar front influences global ocean currents

The Arctic plays a fundamental role in the circulation of water in the oceans of theworld. When warm, salty North Atlantic water reaches the cold Arctic around Green-land and Iceland and in the Labrador Sea, it becomes denser as it cools, and thereforesinks to deeper layers of the ocean. This process of forming deep water is slow, but takesplace over a huge area. Every winter, several million cubic kilometers of water sink todeeper layers, which move water slowly south along the bottom of the Atlantic Ocean.

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Maximum and minimumsea-ice extent.

�Pancake ice.

13The Arctic

Black nilas ice, Laptev Sea

Nilas ice, Laptev Sea.

The icescape from near and far

About a century ago, the Norwegian Arctic explorer Fridtjof Nansen traveled overthe drifting ice pack in his quest for the North Pole. Some days the ice was smoothenough to allow the sleds an easy passage, but oftentimes open water came in theway or huge hummocks turned his travel into arduous work. His description fromearly August 1895 gives a sense of the Arctic icescape:

‘It was as if a giant had thrown the worst iceblocks helter-skelter, strewn deep,wet snow between them and water underneath, so that we sank all the way up toour thighs . . . It was like struggling over mountains and valleys, up and down overblock after block, and ridge after ridge with deep crevices between, not an even sur-face large enough to put a tent on.’Fridtjof Nansen: Fram over Polarhavet, 1897.

Today’s Arctic travelers can get a bird eye’s view of this icescape:‘Flying over the ice is an easy way to appreciate its tectonic activity on a larger

scale, to better understand it as the never-quite-settled surface of the Arctic Ocean.From above, the finger-rafting of huge, transparent sheets of nilas seems like a deli-cate and regular joinery of panes of glass . . . Dark ice cakes below prove to be onescovered with epontic algae and flipped over by animals, or places where walrushave hauled out, rested and defecated. Long streaks on gray-white ice cutting acrossa broad, snow-covered expanse show where leads have recently frozen over. A lowpressure ridge may lead to a dark hole and a patch of reddish snow, a polar bearkill. Streamers of grease ice in patches of open water line up with the wind. In win-ter the leads steam with frost smoke where the (relatively) warm water meets thefrigid air.’Barry Lopez: Arctic Dreams, 1986

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F R I D T J O F N A N S E N A N D H J A L M A R J O H A N S E N , S U M M E R 1 8 9 6

ClimateWeather in the Arctic can be more extreme

than in most other areas of the world, withlow temperatures and strong winds. Theregion includes some of the coldest places onEarth, but temperatures and weather patternsvary greatly among different regions of theAMAP area.

A cold reservoir in a global heat machine

One basic feature of the Arctic climate isthat the sun never reaches high in the sky, evenin summer, which limits the total amount ofincoming solar energy. Moreover, in snow-covered areas as much as 90 percent of theincoming solar energy is reflected back tospace by the snow and ice. Furthermore, thearea loses heat back to space as infrared radia-tion. This is compensated by heat exchange inthe atmosphere and ocean currents that carryrelatively warm air and water masses north-ward and cold air and water southward. TheArctic region also imports moisture from sur-rounding areas.

Seeing the polar area as a refrigerator in theequator-to-pole transport of energy is impor-tant in understanding weather patterns. For

example, the mid-latitude jet streams and thelow- and high-pressure systems embedded inthem are results of the on-going heat exchange.The stronger the temperature differences, thestronger the jet streams. Therefore, the strongeststorms occur in winter. The heat exchange be-tween the Arctic and areas farther south is alsoimportant for understanding contaminant trans-port and global climate change as described inlater chapters.

The High Arctic is cold and dry

The temperature over the Arctic Ocean is mod-erated by heat released through the ice fromthe underlying water, but winter air tempera-tures over the permanent ice pack still fall to–30°C . The cold air cannot hold much mois-ture. Together with the lack of open water, thiscreates very dry conditions in the High Arctic,making a cold desert environment. It mightsnow often, but little falls each time, so thetotal accumulation of snow is relatively low inwinter. Precipitation on northern Greenland,for example, is hardly more than 100 millime-ters per year. Powerful high-pressure systemsin the Arctic often create clear, cold days inlate winter and spring.

Summers in these far-north areas areusually gray and foggy as mild, humid airmoves in over the cold water. Cloud cover insummer ranges from 70 to 90 percent. Theamount of precipitation is still low, however,and temperatures remain between –10 and+10°C, with temperatures most commonlyaround freezing.

Coastal and continental climates can be very different

Farther south, average temperatures and pre-cipitation are governed by the major move-ment of air masses and the proximity to openwater. For example, winter circulation patternsbring cold air from the Arctic Ocean south-ward over North America. Over the continen-tal parts of the Arctic, stable, cold high-pres-sure systems prevail during typical winters.These are particularly well developed over Sibe-ria and northwestern Canada.

The winter high-pressure systems are accom-panied by weak winds and thermal inversions,allowing cold air to gather in the lower one-to-two kilometers of the atmosphere. The lowesttemperatures are usually recorded in typicalcontinental climates, such as the inland areasof Alaska, Siberia, eastern Arctic Canada, andGreenland. Minimum winter temperaturesacross inland areas in the Arctic range from–20 to – 60°C.

There are large temperature differences be-tween winter and summer over the continents.In some parts of Siberia and in the interior ofAlaska, temperatures can range from less than–50°C in winter to above +30°C in summer.

14The Arctic

10241020

10161012

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Canadian low

Low

High

Atmosphericpressure,July means,millibar

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1024

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10321016

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1004 1000

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1012

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Aleutian low

Icelandic low

High

High

2000 m

1000 m

Elevation

Atmosphericpressure,January means,millibar

Patterns of high- andlow-pressure systems inwinter and summer.

Coastal areas often have a maritime climate.Around the Norwegian and Barents Seas, forexample, winter temperatures are on averageonly just below freezing because of the warmNorth Atlantic Current. Even as far north asSvalbard, mean winter temperatures are onlyabout –12°C, about 20°C higher than those atthe same latitude in the Canadian Arctic Archi-pelago. As in most maritime climates, the tem-perature difference between summer and win-ter around the Norwegian and Barents Seas isnot as great as in inland areas. Other areaswith typical maritime climates are Iceland andthe south coast of Alaska.

Semi-permanent low-pressure systemsgovern winds and precipitation

Wind patterns and precipitation in the LowArctic are governed by the low-pressure sys-tems that form over the North Atlantic and theBering Sea, bringing warm, moist air north-ward. These weather systems, the Icelandicand Aleutian lows, gather moisture over openwater and dump it as precipitation when theair is forced to rise. The windward sides ofmountainous areas often have daily rain orsnow. Southern Iceland and parts of the Nor-wegian coast can thus get extreme yearly pre-cipitation, exceeding 3000 millimeters. In the

warm seasons, the Icelandic and Aleutian lowsweaken considerably.

Inland areas of the Low Arctic are generallydry, with decreasing precipitation from southto north. East Siberia, Northern Canada, andGreenland receive less than 140 millimetersper year.

Winds have a great impact on the polarenvironment because they aggravate the chill-ing effect of low temperatures. The open Arc-tic landscape does not slow the winds, whichare also important in mobilizing snow, causingscouring in exposed areas and deposition insheltered locations. In the marine environ-ment, wind affects sea surface stability andincreases mixing in the water column. It alsoproduces ocean currents and influences icedrift and the formation of polynyas.

In winter, unstable conditions in the cold airover the open, relatively warm oceans north ofthe polar front often trigger the formation ofpolar lows. They are much smaller than themore permanent lows, but they bring stormyweather and high winds farther south.

Temperature inversions over ice sheets onland can create local, extremely strong windsin the winter, as cold air surges downhill, usu-ally from the ice toward the sea. Such kata-batic winds are frequent and persistent aroundGreenland.

15The Arctic

Surface air tempera-tures in winter andsummer.

�Svalbard.�

Norilsk, Russia.

January July

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7

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– 8

–13

–18

– 23

– 28

– 33

– 38

– 43

– 48

Surface air temperature, °C

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A circumpolar voyageAs a result of the combined effects of geology,ice, and climate, the lands covered in theAMAP assessment are very diverse. Circlingtwice around the Arctic, first among theislands and then through the continents, givesthe traveler a sample of features that are typi-cal of the different regions..

Icy island outposts

The archipelagos of northern Canada, Green-land, and the islands north of Scandinavia andRussia form the terrestrial outposts farthest tothe north.

Canada’s northernmost area is the world’slargest archipelago, with 20 large and manysmaller islands, some of which are covered byextensive glaciers. The Canadian Arctic Archi-pelago starts with flat to rolling plains in thewest (Banks, Melville, Victoria, Bathurst, andPrince of Wales Islands), building up to rug-ged, ice-capped mountains in the northeast(Baffin, Devon, Axel Heiberg, and EllesmereIslands) toward Greenland. The northernmostland is Ellesmere Island, where the Agassiz icecap covers much of the central part of the is-land. The fjords and straits between the islandsare often blocked by pack ice.

Greenland, which is geologically a part ofNorth America, is a mountainous island. Mostof it is covered by a permanent ice cap, whichreaches elevations of 3000 meters. Many ofthe glaciers extend all the way to the sea, andwestern Greenland produces icebergs at a rateof 300 cubic kilometers per year. The Jakobs-havn Isbrae alone creates 25 cubic kilometersof icebergs per year as the ice tongue glides

forward at an average rate of 20 meters a day.In areas where the ice does not reach the sea,meltwater flows into abundant lakes and riversystems.

Along the coasts, conditions are governedby water temperature. The south-flowing EastGreenland Current brings cold water and icedown from the Arctic Ocean. As much as sixmillion tonnes of ice travels down the coastper year, almost blocking it from open water.Farther south, the warm Irminger Current hascreated a more favorable climate. The currentmixes with colder water, but still manages tobring relative warmth to the coastal areasaround Baffin Bay and southwest Greenland.The coastal waters from Qaqortoq to Sisimiut

16The Arctic

Ellesmere Island,Canada.

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Baffin Island, Canada.

�Kangerlusuaq, East Greenland.

�Narsaq, southern West Greenland.

on the west side of Greenland can be openyear-round, and winter sea ice does not becomethe norm until Disko Bay and farther north.

Most of Greenland that is not covered byglaciers is barren rock with only small patchesof low shrubs or grass. The main tracts of ice-free land in Greenland are in the southwest,the north (Peary Land), and the northeast.The southwestern coast features some grazingland for sheep, and vegetation that includessmall trees.

The Svalbard and Franz Josef archipelagos,the northern island of Novaya Zemlya, andSevernaya Zemlya are extensively ice-clad,mountainous islands, with glaciers calving ice-bergs into the sea. Most of the ice-free land isbare and rocky, since cold and lack of waterhave not allowed much soil to form. Thesouthern Novaya Zemlya island is mostly anice-free coastal plain with continuous per-mafrost. All of the Eurasian island outpostsare mountains rising from the wide continentalshelf. Novaya Zemlya is an extension of theUral Mountains. The highly productive seaaround the islands supports huge populationsof sea birds.

North Atlantic islands: weather ruled by the sea

Iceland was created by volcanic activity alongthe mid-Atlantic ridge some 20 million yearsago. New volcanic rock is constantly forming,and volcanoes erupt regularly. About one tenthof Iceland is covered by lava deposited sincethe last ice age. More than half of the surfacedoes not have any vegetation. About one tenthof the land is covered by glaciers. The climateon Iceland is warmed by the Irminger Current.The extent of sea ice along the coast varies butdoes not normally block shipping.

Another island on the mid-Atlantic ridge isJan Mayen, with its 2300-meter-high volcanicmountain Beerenberg. It erupted as recently as1970.

The North Atlantic part of the AMAP areaalso includes the Faroe Islands, situated 300kilometers north of Scotland and approximately

17The Arctic

Isua, West Greenland.MIN

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half-way between Iceland and Norway. Thisarchipelago has a landscape of low, baremountains, with plenty of grazing land forsheep. The climate is oceanic: humid, change-able, and windy. The ocean temperatures arewell above freezing.

Fennoscandia and Kola: subarctic climate, lakes and forests

Fennoscandia, which includes Finland, Nor-way, and Sweden, rests on old bedrock thathas been worn down to low hills and coastalflats. The Norwegian coast features deepfjords. Along the border between Sweden andNorway, younger mountains form peaks ashigh as 2000 meters, while the landscape gen-erally flattens toward the north and east. Thearea features an abundance of lakes.

The climate in this region is greatly influ-enced by the warm North Atlantic Current.The coasts have a long ice-free period and,except on high mountains, the snow melts insummer. Glaciers build in areas with high pre-cipitation, where summers are too short tomelt the snow in spite of fairly warm tempera-tures. Farther inland, on the Norwegian Finn-marksvidda and in Swedish and Finnish Lap-land, the climate is continental, with warmersummers than along the coast, but consider-ably colder winters.

The vegetation represents a transition be-tween the Arctic and the boreal forest withmany subarctic species. The boreal forestreaches its northernmost point at Finnmarks-vidda in northern Norway, a little south of70°N. There are only patches of permanentlyfrozen ground.

The Russian Arctic: vast expanses of tundra, wetlands and mountains

The Arctic area of the Russian plains (west ofthe Ural Mountains) has been shaped by re-peated build-up and retreat of glaciers thathave left a flatland rich in sediments. The per-mafrost has created a tundra landscape alongthe coast and some forest-tundra closer to theArctic Circle. Summers are cool, wet, andshort, while the winters are long, fairly mild,and snowy.

Going east toward the Ural mountains, theclimate becomes more severe with abundantsnow in the winter. Summers are cool. Most ofthe northern Ural landscape is tundra, withsmall glaciers in the mountains. Immediatelyeast of the Urals, the landscape is again flat,but moving farther eastwards in Siberia, moun-tains reappear.

Much of Arctic Siberia was never glaciated,so pre-glacial soils were never disturbed andthus provide a cover over the bedrock that sus-tains forests. Siberia has one of the most severeclimates in the Arctic, with extremely cold win-ters. Most years, even large rivers freeze to the

18The Arctic

Sarek National Park,Sweden.

Saariselkä, FinnishLapland.

Kolyma River delta,Russia.

Koyuk River, Russia.

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bottom for several months. Permafrost pre-vails, with vast wetland areas and numerousshallow lakes. The landscape is transected byseveral large north-flowing rivers. Many ofthese create deltas where they meet the ocean.The coast is ice-bound for most of the year.

The northeastern corner of Russia has amountainous landscape. In a zone of activelow-pressure systems, its climate is more tem-perate than farther west. In the Chukotkamountains, the peaks reach elevations up to1500 meters.

Alaska: rugged mountains, coastal plainsand volcanic islands

Alaska’s landscape covers a wide range of ter-rains and climates. Rugged mountain rangesstretch across the state in the north and south,reaching 6194 meters at Mt. McKinley. Thereare several active volcanoes in the AlaskaRange, and extensive glaciers in the south-cen-tral and southeastern mountains. Wide coastaltundra plains extend along the northern coastand the southwest. The interior, drained by theYukon river, is forested and has a continentalclimate, with extreme temperature variationbetween summer and winter.

From the west coast, the Aleutian chainstretches westward across the Pacific. The cli-mate on the Aleutian Islands is milder than inthe interior of Alaska, but strong winds arecommon and can create severe weatherthroughout the year.

Permafrost is extensive across the northernthird of Alaska, and is discontinuous for muchof the rest of the state. Along the northerncoast (the Chukchi and Beaufort Seas), sea iceis common even in summer.

Canada: from forests to a frozen archipelago

At the westernmost boundary of Canada’smainland Arctic is the Yukon Plateau, consist-ing of rolling uplands with valleys and isolatedmountains. The climate in this region is sub-arctic and supports forests.

Southwest of this plateau are the CoastMountains with extensive glaciers. To thenortheast of the Yukon Plateau are the Mac-kenzie Mountains. These mountain ranges giveway to the interior lowlands covered by exten-sive wetlands and transected by the MackenzieRiver. The Arctic climate becomes more pro-nounced because of the cold air moving downfrom the Arctic Ocean. Most of the ground ispermanently frozen.

The large Great Bear and Great Slave Lakesextend from the interior lowland eastward intothe Canadian Shield. The shield continues tothe east coast and contains numerous lakesand the vast expanse of Hudson Bay.

Toward the north is the Canadian ArcticArchipelago.

19The Arctic

Chukotka, Russia.

Ivavik, Yukon, Canada.

Hudson Bay, Canada.

Kobuk Valley, Alaska.

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